can anyone recommend some cheap shmups. I don't want to spend $100 on one game :P

games I own:

R type

Gradius 3&4

Metal Slug 4&5

Legendary Wings

Star Soldier

Zanac

ZanaxXZanac

Lifeforce

Raiden 3

Deathsmiles

Soldner X-2

Gekirindan

raystorm